Obstructive Meibomian gland dysfunction (o-MGD) is considered the most frequent cause of evaporative dry eye in the world. O-MGD is associated with aging and contact lens use, but is also associated with many causes of chronic ocular surface inflammation, including allergy and anterior blepharitis. Untreated, o-MGD will lead to atrophy of MGs characterized by infrared (IR) meibography changes, such as segments of discontinuous gland tissue, shortening of glands, and whole or partial gland dropout, leaving fading and poorly defined glands with an ultimate loss of all gland tissue. Symptoms develop from obstruction, causing elevated intraductal pressure, leading to lid tenderness and inflammation with subsequent lipid tear deficiency and dry eye. Treatment has classically focused on an anti-inflammatory approach using antibiotics and steroid along with lid hygiene using heat and lid margin cleansing with optional pressure to the lid to express glands and minimize lid margin inflammation and orifice obstruction. Eye drops are frequently employed in connection with treatments, including, in some cases, eye drops containing autologous serum (AS).
Recently, new approaches to try and reverse glandular obstruction have included thermal pulsation (as practiced under the third-party trademark Lipiflow) and Meibomian Gland Probing (MGP). Lipiflow-style thermal pulsation uses predetermined levels of external heat and pressure to try and force meibum through a duct and orifice obstructed by thickened meibum and intraluminal keratinized debris. In contrast, meibomian gland probing inserts sterile stainless steel wire probes through the natural gland orifice to physically and directly unblock the orifice and ductal obstruction from thickened meibum and other non-fibrotic sources of obstruction. Importantly, MGP also relieves fixed obstructions, such as multifocal periductal fibroses, which are thought to occur along the length of the gland.
Meibomian gland probing is generally described by the present inventor in U.S. patent application Ser. No. 12/305,094, filed on Oct. 18, 2010, the contents of which are herein incorporated by reference in their entirety. The use of MGP allows equilibration of intraductal pressures on both sides of the obstruction with immediate and dramatic relief of lid tenderness and release of sequestered meibum with improved tear break-up time (TBUT). MGP has also been shown to restore meibum secreting gland functionality, significantly increasing the numbers of expressible glands per lid and improve quality and quantity of meibum lipid.
The goal of treating o-MGD should not be limited to symptom relief and stabilizing age or disease associated gland atrophy, but rather to grow Meibomian glands (MGs) and restore a full, functional, healthy, and resilient MG lid population. Consequently, while existing therapies have shown a great deal of promise, further improvements are possible.